An HIV detection platform combining paper-based sample preparation with real-time isothermal amplification. (IMAGE)
Caption
An HIV detection platform combining paper-based sample preparation with real-time isothermal amplification. (left) The handheld device is composed of three main components: a buffer unit at the top, a mixing unit in the middle, and a detection unit at the bottom. The buffer unit contains four reservoirs for housing lysis buffer, binding buffer, and 2 wash buffers, and the sequential release of these buffers are controlled by ball-based valves. The buffer unit and mixing unit can slide with each other, and the mixing unit is integrated with the detection unit through a protrusion beneath the mixing unit. Each valve closes with a bearing ball acting as a plug for the reservoir. As the buffer unit slides along the mixing unit, the valve is activated by a pin in the mixing unit, which pushes the ball up to release the liquid from the reservoir when the pin is aligned with the ball. The detection unit contains a paper pad, which enriches viral RNA as illustrated in the image above the arrow. . (middle) Image of a fully assembled, real-time detector consisting of a handheld microscope mounted on a 3D-printed stand, which houses three compartments at its base for a heater, batteries, and an integrated electrical circuit for controlling temperature. (right) A computer screen with (1) an image of two wells in the detection unit: one well for a sample that had a positive signal while the other well is for the negative control which is dark; and (2) amplification curves from the real-time detector. The computer can be replaced by a smart phone with an App, as demonstrated in this work.
Credit
Microsystems & Nanoengineering
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CC BY